Configuring Explicit Messaging Using SEND_REQ
(Original Document)
About us
Overview
Use the SEND_REQ function block to configure both Modbus TCP and EtherNet/IP connected and unconnected explicit messages.
The Management_Param, the Data_to_Send, and the Received_Data parameters define the operation.
EN and ENO can be configured as additional parameters.
FBD Representation
Input Parameters
Parameter
Data type
Description
Address
Array [0...5] of INT
The path to the destination device, the content of which can vary depending on the message protocol. Refer to a description of the Address parameter for:
Request_Code
INT
For EtherNet/IP:
  • 16#0E: CIP request
For Modbus TCP:
  • 16#50: Generic request
  • 16#51: Read Holding Registers request
  • 16#52: Write Holding Registers request
Data_to_Send
Array [n...m] of INT
The content of this parameter is specific to the Request_Code. Refer to the Data_to_Send descriptions for:
Input/Output Parameters
Parameter
Data type
Description
Management_Param
Array [0...3] of INT
The management parameter, consisting of 4 words.
Output Parameters
Parameter
Data type
Description
Received_Data
Array [n...m] of INT
The EtherNet/IP (CIP) response or the Modbus TCP response.
The structure and content depends upon the specific protocol.